Thursday, March 18, 2010

It seems to make perfect sense: happy people are trusting people. But a new study suggests that, in some instances, people may actually be less trusting of others when they are in a pleasant mood.

“A person’s mood may determine how much they rely on subtle – or not so subtle -- cues when evaluating whether to trust someone,” said Robert Lount, author of the study and assistant professor of management and human resources at Ohio State University’s Fisher College of Business.

In five separate experiments, Lount found that people in a positive mood were more likely than those in a neutral mood to follow cues or stereotypes when determining whether they should trust someone.

If you are predisposed to trust a stranger – because he belongs to the same club as you, or he has a “trustworthy” face -- a happy mood makes you even more likely to trust him.

But if you are predisposed to not trust him, a positive mood will make you even less trusting than normal.

“I think the assumption is that if you make someone happy, they are going to be more likely to trust you. But that only works if they are already predisposed to trust you,” Lount said.

“If you’re a professional meeting new clients, you may think if you buy them a nice lunch and make them happy, you’re building trust. But that can actually backfire if the client has some reason to be suspicious of you,” he said.

The study appears in the March 2010 issue of the Journal of Personality and Social Psychology.

All five experiments involved undergraduate students who took part in various scenarios in which they were put into positive or neutral moods, and were then given the opportunity to show trust or distrust toward a stranger.

In one study, for example, participants were first asked to write one of two short essays. Some wrote about an experience that made them happy while others wrote about what they did in a typical day. Those writing tasks were previously shown to put people in a happy or neutral mood.

The participants were then shown a picture of a person and asked a variety of questions designed to find out how much they would trust him. For example, one question asked how likely the participants thought it would be that the person would intentionally misrepresent their point of view to others.

All the pictures were created by a software program that made the faces appear trustworthy or untrustworthy to most people. A trustworthy person had a round face, round eyes and was clean shaven. An untrustworthy person had a narrow face, narrow eyes and facial hair.

The results were striking: participants in a positive mood evaluated the person with the trustworthy features as more trustworthy than did those in a neutral mood.

Conversely, the happy people were less trusting of the person with untrustworthy features than were those in the neutral mood.

“For those in a good mood, it all depended on the cues that the pictured person gave that suggested whether he was trustworthy or not,” Lount said.

But why would happy people rely more on stereotypes and cues to evaluate a person’s trustworthiness?

“You feel like everything is going OK, so there is no reason to search out new information. You can rely on your previous expectations to guide you through a situation.”

Another one of the experiments provided evidence for that theory. In this experiment, the participants were put in a happy or neutral mood. They were then asked to memorize a nine-digit number, which they would be asked to repeat in a few minutes.

Then, they were shown pictures of untrustworthy faces and asked to rate how trustworthy each face looked.

In this case, people in a neutral mood responded much as did the happy people in the previous experiments – they rated untrustworthy faces as even more untrustworthy.

“In this experiment, people’s minds were busy trying to remember the number so they processed information differently than they normally did,” Lount said.

“They relied more on the cues, just like happy people did.”

Lount said people aren’t aware of this process and don’t even know how their mood is affecting how they evaluate others.

“You need to be careful, especially when you’re happy. You should ask yourself how your mood may be affecting your willingness to trust or distrust another person.”

Yale University scientists have developed a magnetic solder that can be manipulated in three dimensions and selectively heated, and offers a more environmentally friendly alternative to today’s lead-based solders. Their findings appear in the March 1 Early Edition of the Proceedings of the National Academy of Sciences.

Solders are low-melting-point metal alloys that act as a glue for bonding microchips and other electronic devices, such as transistors and resistors, and can be found in everything from computers to cell phones to MP3 players.

Until recently, virtually all solder was made from a tin-lead alloy. But because lead is a toxic substance, there is a lot of interest in trying to find a greener alternative. Recent legislation in Japan and the European Union bans the import of electronics with lead solders.

“We took this as an opportunity to improve solder for the environment, but we also took it as an opportunity to reexamine how to enhance solder in general,” said Ainissa Ramirez, associate professor at the Yale School of Engineering & Applied Science and lead author of the study.

Until now, scientists had difficulty coming up with a suitable alternative for lead-based solders that are just as strong and have a similarly low melting point.

Now Ramirez and her team have developed a non-toxic solder made of tin-silver containing iron particles. Not only is using a tin-silver alloy an environmental advantage, the addition of iron particles has other benefits.

First, the iron makes the alloy much stronger than it would ordinarily be. When an external magnetic field is applied to the molten solder, these particles align themselves within the solder, making it even stronger once it again solidifies.

Second, the iron overcomes the problem of tin-silver having a higher melting point than traditional lead-based solders. By subjecting the solder to an alternating magnetic field, the solder can be selectively heated. This keeps surrounding materials at safe temperatures while melting only the solder itself.

Third, an external magnetic field can be used to remotely manipulate the solder, so it can be moved into hard-to-reach places, such as narrow vertical channels. This means that broken connections within devices can be “self-healed” by applying a magnetic field to melt the solder and attach the ends together.

“There is a whole range of possibilities for this new kind of solder,” Ramirez said. “In addition to helping make the fabrication of microelectronics more environmentally responsible, these new solders have the potential to solve technological challenges.”

A fossil that was celebrated last year as a possible "missing link" between humans and early primates is actually a forebearer of modern-day lemurs and lorises, according to two papers by scientists at The University of Texas at Austin, Duke University and the University of Chicago.

In an article now available online in the Journal of Human Evolution, four scientists present evidence that the 47-million-year-old Darwinius masillae is not a haplorhine primate like humans, apes and monkeys, as the 2009 research claimed.

They also note that the article on Darwinius published last year in the journal PLoS ONE ignores two decades of published research showing that similar fossils are actually strepsirrhines, the primate group that includes lemurs and lorises.

"Many lines of evidence indicate that Darwinius has nothing at all to do with human evolution," says Chris Kirk, associate professor of anthropology at The University of Texas at Austin. "Every year, scientists describe new fossils that contribute to our understanding of primate evolution. What's amazing about Darwinius is, despite the fact that it's nearly complete, it tells us very little that we didn't already know from fossils of closely related species."

His co-authors are anthropologists Blythe Williams and Richard Kay of Duke and evolutionary biologist Callum Ross of the University of Chicago. Williams, Kay and Kirk also collaborated on a related article about to be published in the Proceedings of the National Academy of Sciences that reviews the early fossil record and anatomical features of anthropoids — the primate group that includes monkeys, apes and humans.

Last spring's much-publicized article on Darwinius was released in conjunction with a book, a History Channel documentary, and an exhibit in the American Museum of Natural History. At a news conference attended by New York Mayor Michael Bloomberg, the authors unveiled the nearly complete fossil of a nine-month-old female primate that had been found at the site of Messel in Germany.

But other anthropologists were immediately skeptical of the conclusions and began writing the responses that are being published this month.

"Just because it's a complete and well-preserved fossil doesn't mean it's going to overthrow all our ideas," says Williams, the lead author. "There's this enormous body of literature that has built up over the years. The Darwinius research completely ignored that body of literature."

That literature centers on the evolution of primates, which include haplorhines (apes, monkeys, humans, tarsiers) and strepsirrhines (lemurs, lorises). The two groups split from each other nearly 70 million years ago.

The fossil group to which Darwinius belongs — the adapiforms — have been known since the early 1800s and includes dozens of primate species represented by thousands of fossils recovered in North America, Europe, Asia and Africa. Some adapiforms, like North American Notharctus, are known from nearly complete skeletons like that of Darwinius. Most analyses of primate evolution over the past two decades have concluded that adapiforms are strepsirrhines, and not direct ancestors of modern humans.

The most recent such analysis, published last year in the journal Nature, concluded that Darwinius is an early strepsirrhine and a close relative of the 39-million-year-old primate Mahgarita stevensi from West Texas.

Nevertheless, the scientists who last year formally described Darwinius concluded that it was an early haplorhine, and even suggested that Darwinius and other adapiform fossils "could represent a stem group from which later anthropoid primates evolved."

For example, they note that Darwinius has a short snout and a deep jaw — two features that are found in monkeys, apes and humans.

However, Kirk, Williams and their colleagues point out that short snouts and deep jaws are known to have evolved multiple times among primates, including several times within the lemur/loris lineage. They further argue that Darwinius lacks most of the key anatomical features that could demonstrate a close evolutionary relationship with living haplorhines (apes, monkeys, humans and tarsiers).

For instance, haplorhines have a middle ear with two chambers and a plate of bone that shields the eyes from the chewing muscles.

"There is no evidence that Darwinius shared these features with living haplorhines," says Kirk. "And if you can't even make that case, you can forget about Darwinius being a close relative of humans or other anthropoids."

While today's top-line personal computers boast of dual- or quad-core processors to handle complex workloads, experts predict hundreds or even thousands of core processors may be commonplace within the next decade.

That will enable computers to simultaneously perform a vast range of functions only dreamed about today.

But that poses a daunting task for the engineers who must design memory systems to work with these multi-core processors in a quick, energy-efficient and thermally cool manner.

Zhichun Zhu, University of Illinois at Chicago assistant professor of electrical and computer engineering, has been awarded a five-year, $400,000 National Science Foundation CAREER Award to investigate the architecture for building this next generation of computers.

"We have a lot of challenges facing us," she said. "If each core is running an independent application, each will need a piece of memory to store its data and instructions for the computation."

That is going to require a lot of memory, she said. While today's home computers typically have at least a gigabyte of DRAM -- dynamic random access memory -- to do the job, tomorrow's computers may need a terabyte -- that is a thousand gigabytes -- or more. And the memory will not just be DRAM, but an assortment of types.

Keeping this assortment of memory functioning in a way that doesn't consume vast amounts of power, doesn't overheat, and comes in a compact package as consumers demand will require what Zhu calls universal and scalable memory systems.

"We'll need a new memory architecture that can support diverse memory devices that when put together will work as a whole," said Zhu.

The UIC computer engineer will develop software programs to run simulations that test and validate ways to link diverse memory components that work seamlessly together.

Zhu's grant will support a graduate assistant and will involve undergraduate students who will learn of the problems and potential of the upcoming multi-core era, including the need to write complicated parallel computer programs.

Zhu said parallel computing has been around a long time, but was used mainly by computational scientists at large national laboratories.

"In the future, to get the most performance from personal computers, we'll need to go from sequential to parallel applications," she said. "Maybe all undergraduates will need to learn how to write parallel programming instead of just sequential code."

Like silkworm moths, butterflies and spiders, caddisfly larvae spin silk, but they do so underwater instead on dry land. Now, University of Utah researchers have discovered why the fly's silk is sticky when wet and how that may make it valuable as an adhesive tape during surgery.

"Silk from caddisfly larvae - known to western fly fishermen as 'rock rollers' - may be useful some day as a medical bioadhesive for sticking to wet tissues," says Russell Stewart, an associate professor of bioengineering and principal author of a new study of the fly silk's chemical and structural properties.

"I picture it as sort of a wet Band-Aid, maybe used internally in surgery - like using a piece of tape to close an incision as opposed to sutures," he adds. "Gluing things together underwater is not easy. Have you ever tried to put a Band-Aid on in the shower? This insect has been doing this for 150 million to 200 million years."

The new study, funded by the National Science Foundation, is set for publication this week in Biomacromolecules, a journal of the American Chemical Society.

There are thousands of caddisfly species worldwide in an order of insects named Trichoptera that are related to Lepidoptera, the order that includes moths and butterflies that spin dry silk. Because caddisflies are eaten by trout, fly fishermen use caddisfly lures. Some species spend their larval stages developing underwater, and build an inch-long, tube-shaped case or shelter around themselves using sticky silk and grains of rock or sand. Other species use silk, small sticks and pieces of leaves.

Each larva has a head and four legs that stick out from the tube. The larval case often is conical because it gets wider as the larva grows. A caddisfly larva eventually pupates, sealing off the tube as it develops into an adult fly and then hatches.

Aquatic caddisflies and terrestrial butterflies and moths diverged from a common silk-spinning ancestor some 150 million to 200 million years ago. Caddisflies now live around the world in waters ranging from fast streams to quiet marshes.

"The caddisflies' successful penetration into diverse aquatic habitats is largely due to the inventive use by their larva of underwater silk to build elaborate structures for protection and food gathering," the new study says.

Caddisflies fall into subgroups. Brachycentrus echo, the species Stewart studied, is one of the casemakers, which build their case and then drag it along with them underwater as they forage for food. Some caddisfly larva are retreatmakers, which build a stationary dome-shaped shelter glued to a rock, with a silk net to catch passing food.

Stewart studies natural adhesives, including glue produced in intertidal ocean waters by the sandcastle worm. It has potential as glue for repairing small broken bones.

He got interested in caddisfly larva adhesive silk tape after he was contacted by a Smithsonian Institution scientist who showed him several of the tube-shaped larval cases.

"We looked inside a case through a microscope and saw these silk struts between the rocks and realized this is really interesting," he says. "So I came home and put on my fly fishing boots and started wandering mountain streams looking for caddisfly larvae."

Stewart and study co-author Ching Shuen Wang - who works in Stewart's lab - studied the caddisfly species B. echo from the lower Provo River about an hour south of Salt Lake City. Bioengineering undergraduate student Nick Ashton gathered the fly larvae and figured out how to keep them alive in the lab.

"There's just a fascinating diversity of these insects. Their adhesive is able to bond to a wide range of surfaces underwater: soft and hard, organic and inorganic. If we could copy this adhesive it would be useful on a wide range of tissue types."

Caddisfly larvae extrude adhesive silk ribbon out of an organ known as the spinneret. The products of two silk glands converge there, so the extruded adhesive looks like a double ribbon with a seam the long way. The larvae weave this sticky mesh back and forth around sand grains, sticks or leaf pieces to create the tubes they occupy.

Stewart and colleagues grew caddisfly larvae in aquariums, but with glass beads instead of the sand and rock grains found in streams. The larvae expanded their rock cases using the beads, which were glued together from the inside by wet silk ribbons.

The researchers broke off some beads to obtain clean samples of silk. They analyzed the silk using several methods, including scanning electron microscopy, which showed how silk fibers stitched together the glass beads from inside of the shelter case.

"It's like using Scotch tape on the inside of a box to hold it together," Stewart says. "It's really like a tape more than anything else - a tape that works underwater."

Stewart hasn't studied the strength of the caddisfly silk, but plans to do so.

"Individual threads aren't very strong, but it lays down dozens of them. If we can copy this material and make tape out of it, the bond strength would go up dramatically."

Stewart's study included detailed analysis of the chemistry and structure of the caddisfly silk, showing how it is similar to what silkworm moths produce for use in textiles and even to spider web silk, but with adaptations that make it work underwater.

Stewart says his goal was to characterize the adhesive silk fiber "for the purpose of trying to copy it" so a synthetic version can be used as a surgical adhesive.

He found the caddisfly silk is a fiber made of large proteins named fibroin (fye-bro-in) with an amino acid named serine making up a fifth of the amino acids in fibroin.

The key difference between dry silks from moths and butterflies and wet silks from caddisflies is that the serines in the silk from caddisflies are "phosphorylated," meaning phosphates are added to the serines as the fibroin silk protein is synthesized.

"Phosphates are well-known adhesion promoters used in dental fixtures such as crowns or fillings," says Stewart. "They are also in latex paints that are water-based, and the phosphates increase the adhesion of those paints. The paint industry discovered this fairly recently. Caddisflies have been doing this for at least 150 million years."

The phosphates attached to the serines are negatively charged. Other amino acids in the protein are positively charged. Stewart found that is a key factor in making silk underwater. Chains of proteins - each with alternating regions of positive and negative charges - line up in parallel with positive and negative charges attracting each other.

"Imagine those chains aligned side-by-side, but staggered so the pluses and minuses are lined up, which then forms silk fibers with lots and lots of these protein chains in one fiber," Stewart says. "You wouldn't be able to make shirts out of it, but you might be able to make wet Band-Aids."

Stewart made a counterintuitive finding about how wet silks are made. "These fibroin proteins that make up the silks are water-soluble because of the electrical charges. Ironically - and this is our hypothesis for now - the association of those plus or minus charges makes them water-insoluble. This is how you make a silk fiber under water."

Comparison with amino acids from three other caddisfly species found great similarities, suggesting other caddisflies also use phosphorylation to spin silk underwater.

Stewart says caddisfly silk and sandcastle worm glue are similar: their proteins are heavily phosphorylated and have a large number of positively charged amino acids.

He says the ability to make adhesives underwater now has been identified in four phyla - major categories of living organisms - that include caddisflies, sandcastle worms, mussels and sea cucumbers.

"They came to this underwater adhesion solution completely independently," showing that it repeatedly evolved because of its value in helping the creatures live and thrive, Stewart says.

Darkness can conceal identity and encourage moral transgressions; thus Ralph Waldo Emerson wrote in “Worship” in The Conduct of Life (1860), “as gaslight is the best nocturnal police, so the universe protects itself by pitiless publicity.” New research in Psychological Science, a journal of the Association for Psychological Science, shows that darkness may also induce a psychological feeling of illusory anonymity, just as children playing “hide and seek” will close their eyes and believe that other cannot see them, the experience of darkness, even one as subtle as wearing a pair of sunglasses, triggers the belief that we are warded from others’ attention and inspections.

Psychological scientists Chen-Bo Zhong, Vanessa K. Bohns (both of University of Toronto’s Rotman School of Management), and Francesca Gino (University of North Carolina at Chapel Hill) conducted three experiments to test whether darkness can license dishonest and self-interested behaviors. In the first experiment, participants were placed in a dimly or well-lit room and received a brown envelope that contained $10 along with one empty white envelope. They were then asked to complete a worksheet with 20 matrices, each consisting of 12 three-digit numbers. The participants had five minutes to find two numbers in each matrix that added up to 10. The researchers left it up to the participants to score their own work and for each pair of numbers correctly indentified they could keep $0.50 from their supply of money. At the end of the experiment, the participants were asked to place the remainder of their money into the white envelope on their way out. While there was no difference in actual performance, participants in the slightly dim room cheated more and thus earned more undeserved money than those in a well-lit room.

In the second experiment, some participants wore a pair of sunglasses and others wore clear glasses while interacting with an ostensible stranger in a different room (in actuality participants interacted with the experimenter). Each person had $6 to allocate between him-or herself and the recipient and could keep what he or she didn’t offer. Participants wearing sunglasses behaved more selfishly by giving significantly less than those wearing clear glasses.

In the third experiment, the scientists replicated the previous experiment and then measured the extent to which participants felt anonymous during the experiment. Once again, those wearing sunglasses gave significantly less money and furthermore, those wearing sunglasses reported feeling more anonymous during the study.

Across all three experiments, darkness had no bearing on actual anonymity, yet it still increased morally questionable behaviors. The researchers suggest that the experience of darkness may induce a sense of anonymity that is disproportionate from actual anonymity in a given situation. Zhong explains, “Imagine that a person alone in a closed room is deciding whether to lie to a total stranger in an email. Clearly, whether the room is well-lit or not would not affect the person’s actual level of anonymity. Nevertheless, darkness may license unethical behavior in such situations.”

Water is regarded as a key ingredient for life - and water exists plenty in the universe. Now scientists have found the precious element in a disk around a young star, similar to our Sun. This disk, supposedly the birth place for future planets, contains a hundred times more water than all oceans on Earth. The astronomical observations obtained with the IRAM interferometer appear very promising with regard to solving the mystery around the origin of water in our solar system.

Most of the water in the Earth's oceans likely originated in a tenuous cloud between the stars, which collapsed to form our solar system. Exactly where the water was produced and how the molecules made their way from this giant cloud to a tiny planet like Earth some 4.5 billion years ago is one of the key questions in the study of our origins.

While astronomers cannot turn back the clock to observe our own young solar system, they can study planetary systems in formation around other nearby young stars. The IRAM Interferometer on the Plateau de Bure in the French Alps has pinpointed for the first time the location of the bulk of the hot water vapour in the rotating disk around a very young star, analogue to our Sun.

Because of obscuration by the large amounts of water in our own atmosphere, astronomical observations of normal water (H216O) require satellites such as the recently launched Herschel Space Observatory. However, about 1 in 500 water molecules in space contain the heavier 18O isotope. Some signatures from this heavier water (H218O) are able to penetrate the Earth's atmosphere and reach the IRAM telescopes. Since telescopes on Earth are much larger and see a hundred times sharper than any existing satellites, this allows astronomers to zoom in on the forming stars and determine the location of water.

The astronomers Ewine van Dishoeck from the Max Planck Institute for Extraterrestrial Physics in Garching and Leiden Observatory, and Jes Jørgensen from the University of Bonn and the Centre for Star and Planet Formation in Copenhagen, used the IRAM Plateau de Bure interferometer to look for heavy water (H218O) around a young star, NGC 1333 IRAS4B that formed only 10,000 - 50,000 years ago. The astronomers found that most of the steam around the young star is located within the inner 25 Astronomical Units of the rotating disk. This distance corresponds approximately to the orbit of Neptune in our own solar system (1 AU is the distance Earth-Sun, about 150 million kilometres).

Previous observations of this protostar had suggested that water vapour is pouring down from the cloud and accretes onto the disk. The IRAM data show that the amount of water actually in the disk is a factor of hundred larger than in any such shocks - about 100 times more than the content of Earth's oceans.

'The water is likely located in a hot layer just above the disk midplane, where most of the available oxygen is driven into water by chemical reactions,' says Ewine van Dishoeck. 'We now know that most water enters the disk in the form of ice around dust grains from the cold collapsing cloud, and that these "icy mantles" evaporate in the higher temperatures close to the young star.'

'These observations of water vapour have opened up a whole new avenue to study water in young solar systems, complementary to that possible with satellites,' explains Jes Jørgensen, lead author of the paper. 'Only the IRAM Plateau de Bure Interferometer is currently able to catch and image these very weak signals of the water isotopologue. Moreover, the long wavelengths at which the Plateau operates allow us to see much deeper into the disk and we can thereby study the physical and chemical processes that control the early evolution of these disks that may set the stages for the eventual formation of planets.'

Over the next three years, the Herschel Space Observatory will survey normal water in many star-forming clouds in our own and other galaxies. Combined with similar ground-based observations, astronomers will be able to determine exactly how much water is located where and at which stage of the evolution of a young star. "The combined access to the powerful IRAM telescopes and the Herschel-PACS instrument makes the Max Planck Institute for Extraterrestrial Physics a unique environment to carry out such comprehensive studies of water in young solar systems", says Ewine van Dishoeck.

A new study by researchers at Wake Forest University School of Medicine reveals how extremes of sleep – both too much and too little – can be hazardous to your health – especially for young minority women, a group most affected by obesity and chronic metabolic disease. The findings also indicate that there’s more to “fat” than what we choose to eat – social factors such as the need to work three jobs in a bad economy – could be causing dangerous fat deposition around vital organs.

“We put a lot of stock in diet,” said Kristen G. Hairston, M.D., M.P.H., an assistant professor of endocrinology and metabolism and lead author on the study. “But this study brings up some interesting questions about the way we live. We may need to start looking at other behaviors – besides daily food choices – that could be contributing to the obesity epidemic in younger age groups.”

In individuals under 40, the study showed a clear association between averaging five hours or less of sleep each night and large increases in visceral fat, or fat around the organs. Of the study participants under 40, Hispanic men and black women were the largest groups to report getting such little sleep.

Short sleep has become more common in the United States and minorities are disproportionately affected, said Hairston, an affiliate of the Maya Angelou Center for Health Equity, part of the School of Medicine. They are also more prone to metabolic conditions, including increased rates of obesity, insulin resistance and type 2 diabetes. The study suggests that part of the explanation for higher rates of metabolic disease in this population may lie in the association between sleep duration and fat deposition.

But sleeping the day away won’t do much to better one’s health, either. The researchers found that getting more than eight hours of sleep on average per night has a similar – though less pronounced – affect and is a problem most commonly seen in Hispanic women of all ages.

Surprisingly, the connection between extremes of sleep and accumulation of visceral fat was seen only in patients under 40, Hairston said.

“We don’t really know yet why this wasn’t seen in participants over 40, but it was clear that, in individuals under 40, it is worse to get five or less hours of sleep on average each night than it is to get eight or more hours,” Hairston said. “However, both may be detrimental and, in general, people should aim for six to eight hours of sleep each night.”

The study appears in the March issue of Sleep, the journal of the Associated Professional Sleep Societies, LLC.

The study raised important social questions for researchers, Hairston said, such as why so little sleep is such a problem in black women under age 40 and what circumstances may be contributing to their sleep patterns and likely to obesity and chronic disease development?

“This was certainly just a starting point,” Hairston said. “We definitely know that a relationship exists between sleep and obesity. Now we need to know how this relationship can be modified.”

Hairston added that it will be important for future obesity research to consider sleep patterns and the effect they can have on outcomes. Until the connection is understood, physicians should consider gathering information about sleep patterns just as they do other vital information when seeing patients. This information is especially relevant when treating patients about to make or in the middle of life transitions, such as college, marriage and childbearing, because such times are often associated with sleep deprivation in younger years.

“That information may help a physician put into context other issues going on in the patient’s life which may be affecting their overall health,” Hairston said.

The same antifreeze proteins that keep organisms from freezing in cold environments also can prevent ice from melting at warmer temperatures, according to a new Ohio University and Queen’s University study published in the Early Edition of the journal Proceedings of the National Academy of Sciences.

Antifreeze proteins are found in insects, fish, bacteria and other organisms that need to survive in cold temperatures. These proteins protect the organisms by arresting the growth of ice crystals in their bodies. The new study not only has implications for understanding this process in nature, but also for understanding the superheating of crystals in technologies that use superconductor materials and nanoparticles.

Twenty years ago, researchers proposed that antifreeze proteins can create superheating by suppressing melting at temperatures higher than the equilibrium melting point.

“During recrystallization, a larger ice crystal grows while a smaller one melts. Antifreeze proteins can help control both of these processes,” explained Ido Braslavsky, an associate professor of physics and astronomy at Ohio University who worked on the study with lead author Yeliz Celik, a doctoral student in physics at Ohio University, and Professor Peter Davies of Queen’s University in Canada.

The team’s study, supported by the National Science Foundation and the Canadian Institutes for Health Research, presents the first direct measurements of the superheating of ice crystals in antifreeze protein solutions, Celik said.

In addition, the researchers provide the first experimental evidence that superheated ice crystals can be stabilized above the melting point for hours, at a maximum temperature of about .5 degree Celsius. Superheated crystals rarely stay stable for long periods of time, and previous studies showed that stabilization only occurs under unique conditions, Braslavsky explained.

The researchers used two techniques in the study, fluorescence microscopy and sensitive temperature control of a solution within a thin cell. In order to track the position of the antifreeze protein on an ice crystal, the researchers attached a second protein to the antifreeze protein—the green fluorescent protein, which glows under certain conditions. The scientists then placed the antifreeze protein solution in the thin cell, which allowed them to observe the fluorescence signal from the protein while finely controlling the ice crystal’s temperature.

Although the study reveals that these proteins can suppress ice melting up to a certain point, the protein’s ability to suppress ice growth is much stronger. The hyperactive antifreeze proteins used in the study were more capable of suppressing melting than the moderately active ones, Braslavsky said.

These findings potentially could make the process of ice recrystallization inhibition more efficient for applications such as maintaining the quality of frozen foods, Braslavsky said.

“Antifreeze proteins that inhibit growth and melt are essential for protection against freeze and thaw damages,” he said. “Big crystals (that occur in the recrystalization process) separate cell walls and damage the integrity of the tissue.”